The Belfast Trust and Western Trust were worst affected, axing almost 500 operations between them.

The alarming figures lay bare the extent of the crisis caused by a chaotic winter at Northern Ireland's under-pressure emergency departments.

Trusts were forced to axe routine surgery after A&E units were swamped by patients.

And there are warnings that the situation will get even worse, with people's lives being put at risk.

Patricia McKeown from the health workers' union Unison said a £19m rescue package to deal with the problem two years ago has now been slashed to just £7m.

"This is crisis management, and it has been crisis management for far too long," she told the Belfast Telegraph. "We are now seeing the consequence of this on a daily basis.

"This is only going to worsen dramatically and it is time the new minister, his department and the system started paying attention."

Details of cancelled operations were disclosed by the Health Minister after an Assembly question by UUP MLA Roy Beggs.

Simon Hamilton said that between January and March, 707 elective (non-urgent) operations were called off due to "hospital pressures".

The worst month was January, when 348 operations were axed across the five health trusts - around 11 a day.

The problems continued into February, when a further 275 procedures were cancelled.

Even as the pressure eased in March, 82 operations were still called off.

Across the three-month period, the Belfast Trust cancelled 271 operations.

It called off routine surgery in the first week of January and again in early February after admitting staff were facing ongoing and significant pressures in A&E.

At the time, one man who took his 87-year-old father to the Royal Victoria Hospital described how people were "packed like sardines" in the emergency department.

Meanwhile, the Western Trust called off 234 operations, while the Northern Trust axed a further 140 procedures.

Ms McKeown said that far from improving, the situation would only worsen, and warned people's lives were being put at risk.

She added: "Two years ago £19m was invested to deal with the backlog and the queues, and that didn't work. This year they are putting £7m in, so we will see a lot more than eight operations a day cancelled.

"It is not just happening with elective surgery. Those queues are forming at A&E departments, and for cancer biopsies.

"People are at risk, and it is not just the unions saying it. Right-thinking people at the top of the system are saying it too."

Mr Beggs, who obtained the figures, said it was obvious more investment was urgently needed.

"Clearly, there is not sufficient resources to cope with demand," he said.

The East Antrim MLA warned that leaving patients on waiting lists could cost the system more in the long run.

"If timely procedures are not carried out, there is a risk of illnesses progressing and more and more demand on the health service," Mr Beggs cautioned.

The Health Minister Simon Hamilton said of the figures: "Such cancellations may be considered by HSC Trusts at times of increased unscheduled care pressures, as part of their escalation plans to improve patient flow and ensure sufficient bed capacity to accommodate unscheduled admissions."